ABSTRACT
From the whole electromagnetic spectrum, extending from DC to gamma rays, microwaves cover frequencies ranging from 300 MHz to 300 GHz, with equivalent wavelengths ranging from 1 m to 1 mm (Sorrentino and Bianchi 2010). High frequencies and short wavelengths of the microwaves provide unique opportunities for their application in various life sectors including, among others:
◾ Wireless networking and communication ◾ Radio-astronomy ◾ Weather forecasting and remote sensing ◾ Automotive aids and control ◾ Civil and military surveillance systems ◾ Healthcare and biomedicine ◾ Microwave imaging, test of materials, objects, or constructions ◾ Food processing ◾ Basic and applied research ◾ Application in the field of energy
A vast spectrum of application possibilities requires suitable microwave (MW) sources and a variety of detectors having features good for each specific sector of application. e process of detection of radiation involves two requirements to be fulfilled. First, radiation has to be able to invoke any changes (physical, chemical, etc.) in a detector and, second, the latter should produce any sensible signal, preferably electrical or optical. In practice, MW radiation is usually detected using substitution techniques based on its heating effect or by rectification.
